Secondary organic aerosols (SOA) are one of the main sources of uncertainty in the current understanding of the Earth’s climate. Agriculture contributes to primary aerosol emissions, but there is no estimate of SOA formation from gaseous precursors. Organic waste products such as sewage sludge are applied to cropland as fertilizers. In this work, we show that sewage sludge is an unaccounted source of nucleation precursors, such as skatole (C₉H₉N). Skatole emission and nucleation rates up to 1.1 × 10⁶ cm⁻³ s⁻¹ owing to ozone reactivity were measured in the laboratory. Our results show that SO₂ plays a key role in the oxidation of skatole and leads to intensive new particle formation. The products of ozone reactions with skatole and the possible ozonolysis reaction mechanism are discussed. This nucleation mechanism might aid our understanding of the organic waste agricultural recycling contribution to the aerosol balance in the atmosphere. Based on the measured particle emission flux, the surface area of sewage sludge spread in France and the time before sewage sludge incorporation into the soil, a rough estimate of the annual quantity of particles generated by this agricultural activity is in the range of one ton, which represents ~0.03% of the total PM_1.0 emissions from the agricultural and forestry sectors in France. As spreading occurs over only a few days (mid-summer), these emissions may locally be of great concern for local and regional air quality during this period of the year.

在目前对地球气候的了解中，二次有机气溶胶（SOA）是不确定性的主要来源之一。农业促成主要的气溶胶排放，但没有估计由气态前体形成的SOA。有机废料（例如污水污泥）作为肥料施用于农田。在这项工作中，我们表明污水污泥是成核前体（例如粪臭素（C ₉ H ₉ N））的未知来源。在实验室中测量了由于臭氧反应性而产生的高达1.1×10 ⁶  cm ^-3  s ^-1的溜溜形核发射和成核速率。我们的结果表明SO ₂在粪臭素的氧化中起关键作用，并导致密集的新颗粒形成。讨论了与粪臭素发生臭氧反应的产物以及可能的臭氧分解反应机理。这种成核机制可能有助于我们了解有机废物农业循环利用对大气中气溶胶平衡的贡献。根据测得的颗粒物排放通量，法国污泥的表面积分布以及污泥掺入土壤的时间，这种农业活动每年产生的颗粒物的粗略估计为一吨，约占总PM _1.0的0.03％法国农业和林业部门的排放。由于扩散仅在几天内（夏季中旬）发生，因此在一年中的这段时间内，这些排放可能会在当地引起当地和地区空气质量的极大关注。